The methods and systems disclosed herein are related to the art of digital image processing.
By way of background, the emerging digital printing technology is changing the dynamics of traditional security printing. Highly sophisticated and technologically advanced reprographic systems are no longer tools limited to the skilled technician but are now widely available to the general public. Ease of use and versatility, facilitated by user-friendly control panels, permit an unskilled user to make faithful full-color reproductions of many documents. Reproduction quality, ease of access, and relative freedom from discovery combine to create an atmosphere within which many individuals may experiment with forgery, tampering, unauthorized replication of sensitive documents, committing the so-called crime of opportunity. Furthermore, a low reproduction cost may encourage counterfeiting documents of relatively low value, such as tickets, merchandise packaging, coupons, and prescriptions.
Typical threats to a document include: (i) counterfeit/imitation; (ii) forgery; (iii) alteration; (iv) photo and/or signature substitution; and (v) counterfeit from cannibalized documents. Different security features fit different documents. Security features suitable for Passports, may differ for those suited for ID Cards, Driving Licenses, etc.
There are generally three levels of Physical Security Features. Level I includes security features are seen by the naked eyes (overt security features) such as: ID pictures, holograms, optical variable inks (OVI), thermo-chromic inks, metallic security threads, personalized shadows, and graphic designs (watermarks, deformation pattern, guilloche, intaglio, rainbow printing, etc.). Level II includes hidden security features authenticated by using simple devices (covert security features) such as a magnifying glass, a UV (ultraviolet) lamp, a two-dimensional (2D) barcode reader, a smart card reader, special simple lenses, and other electronic devices and biometric data verification. Typical measures include micro-text, UV and IR (infrared) inks, magnetic inks, tagged inks and toners. Level III includes hidden security features authenticated at a forensic laboratory level using special equipment.
Maintaining the integrity of a document and protecting it from unauthorized alteration is one of the topics that have recently drawn more attention. The watermarking-based method has been extensively studied for protecting pictorial images. The basic idea is to produce a compressed copy of the original image and embed it as digital watermarks into the image at a different location. By comparing the image and the digital watermarks, tampering can be detected. Similar methods can be applied to protect text documents. A duplicated version of the text information, with possible compression and coding is printed invisibly using the security printing technologies (e.g., infrared (IR) marks, UV marks, and/or microprints). If the counterfeiter modifies the text without changing its invisible duplication, it can be detected by comparing these two versions. These technologies belong to level III (covert) and II (assisted) features in security printing terminology. They are generally effective and reliable. However, their main disadvantage is they require additional detection equipment or tools.
The exemplary embodiments disclosed herein contemplate new and improved methods and systems that resolve the above-referenced difficulties and others.